A gas turbine engine generally includes a fan and a core arranged in flow communication with one another. Additionally, the core of the gas turbine engine generally includes, in serial flow order, a compressor section, a combustion section, a turbine section, and an exhaust section. In operation, air is provided from the fan to an inlet of the compressor section where one or more axial compressors progressively compress the air until it reaches the combustion section. Fuel is mixed with the compressed air and burned within the combustion section to provide combustion gases. The combustion gases are routed from the combustion section to the turbine section. The flow of combustion gases through the turbine section drives the turbine section and is then routed through the exhaust section, e.g., to atmosphere.
More particularly, the combustion section includes a combustor having a combustion chamber defined by a combustor liner. Downstream of the combustor, the turbine section includes one or more stages, for example, each stage may a plurality of stationary nozzle airfoils as well as a plurality of blade airfoils attached to a rotor that is driven by the flow of combustion gases against the blade airfoils. The turbine section may have other configurations as well, e.g., the turbine may be a counter-rotating turbine without stationary nozzle airfoils. In any event, a flow path is defined by an inner boundary and an outer boundary, which both extend from the combustor through the stages of the turbine section.
Typically, the inner and outer boundaries defining the flow path comprise separate components. For example, an outer liner of the combustor, a separate outer band of a nozzle portion of a turbine stage, and a separate shroud of a blade portion of the turbine stage usually define at least a portion of the outer boundary of the flow path. Utilizing separate components to form each of the outer boundary and the inner boundary may require one or more seals at each interface between the separate components to minimize leakage of fluid from the flow path. Thus, a great number of parts may be required to construct a flow path assembly, which can increase the complexity and weight of the gas turbine engine. Further, although seals may be provided, utilizing separate components in the flow path assembly provides several points for leakage of the fluid from the flow path. Increased weight, complexity, and leakage can negatively impact engine performance, as well as assembly of the engine during manufacturing.
Accordingly, improved flow path assemblies would be desirable. For example, a unitary outer boundary structure extending through the combustion section and at least a first stage of the turbine section would be beneficial. Further, a flow path assembly comprising a unitary inner boundary structure and a unitary outer boundary structure would be useful. Additionally, a flow path assembly comprising an integral combustor dome, inner boundary structure, and outer boundary structure would be helpful. Moreover, a gas turbine engine having a flow path assembly with a unitary outer boundary structure would be advantageous.